I've never worked with PHP chart libraries, but if you're willing to do Javascript, which would be nice if you want to implement an AJAX solution at a later time, I'd suggest flotr2. Most of my friends who are devs suggest flot. They're pretty comparable so do some research if you want to look into something like that. Google also has its own chart library called Google Charts you can externally link to called Google Charts. PHP chart libraries do exist but I don't have experience with them so I can't make a suggestion which to use.

Thank you for pointing me in the right direction. I tried out flotr2 and it is easy as pie. With a little searching I came up with a good post on StackOverflow about how to integrate the chart with database data generated from PHP. Excellent!

Cheers,Steve

PS: I would not touch anything from Google because most of their open source products are here today gone tomorrow. Look at what they just did with Google Code.

Hi there, I had necer used PHP charting library. Rather than PHP why don't you go for Javascript chating libraries. It allows you to add all the data visualization features to without any plugins and flash.